This invention relates to breaking or crushing machines, particularly hammer crushers, which comprise a housing having a stationary wearing wall against which the material to be broken or crushed is beaten, ground or otherwise smashed, usually by hammers mounted on a rotor which revolves within the housing.
The wearing wall is usually composed of a number of individual replaceable wearing plates which are removably fixed on the inside of the housing wall. However, the fixing of the wearing plates on to the housing wall of the machine poses certain problems, because the wearing plates are naturally subject to wear, whereas the fixing means should not be subject to wear. Therefore the most obvious way of fixing, namely screwing the wearing plates to the wall, is generally unsuitable because the screw connections also wear away as the plates wear and thereby lose their holding action.
Attempts have been made to overcome this fixing problem, and one example is disclosed in German Auslegeschrift No. 1,165,975. The solution proposed is, however, not completely satisfactory. In the fixing disclosed, screw connections are indeed avoided. Instead, wedges are used, the wedges being secured to the inner face of the housing wall and engaging in grooves on the inner face of each wearing plate. With this form of construction, the wearing plates mutually support one another, but the supporting action deteriorates with increasing wear of the plates, especially when the portion of the housing wall on which the wearing plates are mounted is curved only slightly or not at all. Consequently, it is not possible in this form of construction to dispense with the fixing wedges. Furthermore, since the processes within a breaking or crushing machine can only be observed from outside with difficulty, it is unavoidable that the wear of the plates, which for economic reasons one naturally wishes to use as long as possible, reaches a degree at which the wedges become released and damaged. In this case it is necessary not only to replace the wearing plates themselves, which is a relatively simple operation, but also to replace the wedges. This can prove difficult because the face of the housing wall remote from the interior of the machine must be accessible for this purpose, a condition which in many cases is not wholly fulfilled.